This application claims the priorities of Japanese Patent Application No. HEISEI 11-338380 filed on Oct. 21, 1999 and Japanese Patent Application No. 2000-105668 filed on Feb. 18, 2000, which are incorporated herein by reference.
This invention relates to a vertical pump, particularly improvement of a vertical pump having an impeller without a driving shaft.
A general liquid pump is provided with a driving shaft at a rotational center of an impeller arranged in a casing, and the driving shaft is driven to be rotated by a motor so that a liquid is sent. Therefore, a bearing for supporting the driving shaft to the casing rotatively, and a seal mechanism for preventing an inner liquid from flowing out from the bearing portion were required. Causes of malfunction of a pump are mostly centered at the seal mechanism and the bearing portion.
Particularly in the case where a liquid sucked up by a pump contains a solid component such as sludge, this sludge penetrates into bearing and seal portions and abnormal abrasion occurs, and there arises a problem that a life of the pump is shortened.
It has been a long time since a seal-less pump in which the seal is eliminated and risk of liquid leakage is lowered was developed. As this seal-less pump, there are a canned motor pump and a magnet pump having an impeller, and a diaphragm pump for sending a liquid by means of reciprocation of a film.
In the canned motor pump or the magnet pump, a driving shaft and a bearing exist in a liquid. For this reason, normal lubricant cannot be used for a bearing portion, and a transfer liquid functions as lubricant and coolant, and it is unavoidable that abrasion chips of the shaft and bearing are mixed in the transfer liquid. Moreover, idling without a liquid occasionally causes a damage to the bearing.
This becomes a big problem particularly in the case where these pumps are used as a pump for sending a cleaning super pure water which is used a lot at the time of producing a semiconductor.
Meanwhile, since a driving shaft and a bearing do not exist in a liquid in the diaphragm pump, a discharged liquid is not polluted much, but the discharged liquid is pulsated and a film easily malfunctions. Furthermore, a pump head can be high but a discharge amount is small. As a result, in the case where a lot of transfer is executed, this pump becomes extremely more expensive than another pumps.
The present invention is devised in order to solve the above problems in the prior arts, and its object is to provide a vertical pump in which a discharged liquid is hardly pulsated and polluted and efficiency is high.
In order to achieve the above-mentioned object, the present invention provides a vertical pump, comprising: a rotating body having an impeller arranged with its axial center being vertical, and a cylindrical rotor fixed to an upper portion of said impeller with their axial center being aligned with each other, a main portion of said cylindrical rotor being composed of a good conductor; a casing for housing said rotating body with a gap rotatively; and rotation magnetic field generating means for applying a rotational force to said cylindrical rotor, said means facing said cylindrical rotor.
Preferably, in the present invention, wherein said casing includes: an impeller chamber having a suction port at its lower center and a discharge port at its side portion, said impeller chamber for storing said impeller; and a rotor housing having an inner cylinder and an outer cylinder made of non-magnetic high-electric resistant materials, and a cover section for covering upper portions of said cylinders, said cylindrical rotor being arranged between said inner cylinder and said outer cylinder with a gap rotatively, said rotor housing being connected integrally with the upper portion of said impeller chamber.
Preferably, in the present invention, wherein said rotation magnetic field generating means includes inner rotation magnetic field generating means and outer rotation magnetic field generating means, for applying rotational forces to said cylindrical rotor, which are arranged so as to respectively face an outer side of said outer cylinder and an inner side of said inner cylinder.
Preferably, in the present invention, wherein a magnetic cylinder is arranged on said cylindrical rotor concentrically, and an up-and-down position of a cross sectional centroid of the magnetic cylinder in the state that said cylindrical rotor is stopped is in a center position of said rotation magnetic field generating means in the up-and-down direction, and said cylindrical rotor is driven to be rotated, and the rotating body including said cylindrical rotor rises.
Preferably, in the present invention, wherein lengths of cores in the up-and-down direction forming polarities of said outer rotation magnetic field generating means and said inner rotation magnetic field generating means are the same, and those means are in the same level, and lengths of the cores and said magnetic cylinder in the up-and-down direction are equal to each other, and said magnetic cylinder is embedded concentrically from top of said cylindrical rotor, and said magnetic cylinder is in a thickness-wise center position of said cylindrical rotor.
Preferably, in the present invention, wherein clean liquid supply means having an introduction hole is provided to an upper position of said rotor housing so as to supply a clean liquid from an upper portion of said rotor housing.
Preferably, in the present invention, wherein said clean liquid supply means has a filter which filtrate a transfer liquid discharged from the discharge port of said outer casing so that the transfer liquid filtrated by the filter is supplied to the upper portion of the rotor housing.
Preferably, in the present invention, wherein said inner rotation magnetic field generating means and said outer rotation magnetic field generating means are composed of an inner stator and an outer stator which allows alternating currents to flow so as to generate rotation magnetic fields.
Preferably, in the present invention, wherein a cooling tank where the inner stator and the outer stator are cooled by an insulating liquid is provided, and cooling means for cooling the insulating liquid is provided to the cooling tank.
Preferably, in the present invention, wherein the cooling means for cooling the inner stator has a cooler and a circulating pump of the insulating liquid.
Preferably, in the present invention, wherein said inner rotation magnetic field generating means and said outer rotation magnetic field generating means are composed of an inner magnet and an outer magnet which are driven to be rotated by a motor, and said motor is rotated so as to apply a rotational force to said cylindrical rotor.
Preferably, in the present invention, wherein a bottom plate which is supported by a supporting cradle is provided to said rotor housing, and an impeller casing section, which covers said impeller from a lower part so as to form said impeller chamber is attached to the bottom plate in a covered state.
Preferably, in the present invention, wherein a first annular magnet is provided to the upper portion of said impeller, and a second annular magnet which repulses said first annular magnet is provided to a lower portion of said inner bottom plate of said inner cylinder facing the upper portion of said impeller.
Preferably, in the present invention, further comprising: a movable annular magnet arranged around a suction passage of the lower portion of said impeller: and a fixed annular magnet arranged to the impeller casing section and facing said movable annular magnet, wherein said movable annular magnet and said fixed annular magnet repulse each other on their countered surfaces.
Preferably, in the present invention, wherein an aileron which pushes out a liquid at the upper portion of said impeller by rotation of said impeller is formed on an upper surface of said impeller main plate.
Preferably, in the present invention, wherein a resistant cylinder which projects downward is formed on a lower surface of said rotor housing.
Preferably, in the present invention, wherein said impeller main plate has an opening whose center is a rotational axis of the plate, and an equalizer plate which is hung from a lower surface of said rotor housing is provided to the opening.
Preferably, in the present invention, further comprising: a movable aileron which is projected from said rotating body to a peripheral direction: and a fixed aileron which is projected from said casing inwardly are provided, wherein an area of countered portions of said movable aileron and said fixed aileron changes by up-and-down movement of said impeller, and when said impeller moves upward, the area of the countered portions decreases and a transfer amount of the liquid into the upper portion of said impeller increases, and when said impeller moves downward, the area of the countered portions increases and a transfer amount of the liquid into the upward portion of said impeller decreases.
Preferably, in the present invention, comprising: an upper pressure sensor for detecting a liquid pressure on the upper portion of said impeller; a lower pressure sensor for detecting a liquid pressure between the lower portion of said impeller and said impeller casing section; a pressure adjusting tube for, when a difference (P1-P2) between the upper pressure P1 and the lower pressure P2 becomes larger than a fixed value xcex4P, discharging the liquid on the upper portion of said impeller, and when the difference (P1-P2) becomes smaller than the fixed value xcex4P, feeding a liquid to the upper portion of said impeller; and a controller for controlling the discharge and feeding by means of said pressure adjusting tube.